Rotary electric switch



Feb. 28, 1956 R. F, GATES 2,736,780

ROTARY ELECTRIC SWITCH Filed Nov. 13, 1955 INVENTOR.

///5/ITTOR NE 225;

United States PatentO ROTARY ELECTRIC SWITCH Rowland F. Gates, Port Credit, Ontario, Canada, assignor to The Arrow-Hart & Hegeman Electric Company, Hartford, Conn., a corporation of Connecticut Application November 13, 1953, Serial No. 391,866 3 Claims. (Cl. '200168) This invention relates to electric switches. More particularly it relates to a rotary electric switch construction useful generally but particularly adapted for use in control of heating circuits for an electric range or the like.

It is an object of the invention to provide an improved construction for slow-break rotary electric switches which may be more economically constructed and assembled than heretofore without sacrificing quality and reliability.

Another object of the invention is to provide, in a rotary electric switch wherein the operating member comprises a cover, a simplified means for attaching the cover to the base which is normally concealed by a decorative element but yet available without great dilficulty in case of need. A related object is to provide for snapping said element into place, avoiding the need for special tools.

Other objects and advantages of the invention will become apparent as it is described in connection with the accompanying drawing.

In the drawing:

Fig. l is a plan view of the switch embodying the invention.

Fig. 2 is a bottom view of the switch.

Fig. 3 is a plan view of the base with the cover removed.

Fig. 4 is a section view taken along line 4--4 of Fig. 1.

Fig. 5 is a perspective view of one of the stationary contact plates used in the switch.

Fig. 6 is a perspective view of one of the movable contacts used in the switch.

Referring to the drawing, a circular disc-like base 10 molded from insulating material is hollowed out in its upper face to receive the contacts and operating mechanism of the switch. An exterior peripheral shoulder 12 suitable to rest upon a panel or mounting plate is provided by enlargement of the base, thus enabling the base to be mounted conveniently within a circular hole in the mounting plate or other part of an electric range. Fitted into the open top of the base is a circular disclike cover which is held to the base by a centrally located spindle 14 which passes through a central bore in the base and in the cover. The lower end of the spindle 14 has a head 16, the underside of which engages the bottom of the base. The top or outer end of the spindle 14 is bifurcated and the bifurcations are spread into a recess 22 formed in the center of the top of the cover. In that way the cover is rotatably attached to the base.

The cover is provided with a diametrical raised handle portion or ridge 20 which may conveniently be grasped by the thumb and forefinger of a person to operate the switch. In the handle portion is formed a channel communicating with diametrically opposite radial recesses 24, 24' formed at the ends of the handle portion 20. A small passageway is provided between the bottom portions of the radial recesses 24, 24 and the underside of the cover beneath a peripheral skirt portion 26 thereof. The skirt portion 26 is of such diameter as to fit within the open top of the base 10 so that the current-carrying parts beneath the cover and within the base are completely covered and isolated from contact from above by the person operating the switch.

In order to conceal the bent over bifurcations of the switch spindle and at the same time to provide a decoration on the cover, a thin arched metallic strip 30 may be seated within the channel in the handle portion of the cover. This decorativestrip 3.0 is made flexible so as to enable its insertion or assembly upon the cover after the switch has been otherwise completely assembled. For that purpose, the ends 32, 32' of the strip 30 are bent outwardly so that as one end 32 is inserted in the radial recess 24 and into the passage at the bottom thereof, the strip may be bent or arched more sharply and the opposite end 32 pushed down into the opposite radial recess 24'.

In that way a decoration is provided upon the top of the cover while at the same time the top of the spindle is concealed. Nevertheless should it become necessary to move the .cover,'the strip 30 may be flexed and the ends 32, 32' removed from the passages 24, 24 under the skirt 26 whereby the stripis disengaged from the cover. Thereupon the bifurcations 22 are available for manipulation to enable the spindle to be removed from the cover and base and the parts made available as the cover is removed.

The operation of the switch is accomplished by circular concentric cam surfaces, for example 34 and 36, which are spaced at different distances from the center of the cover on the bottom face thereof. These cam surfaces are adapted to engage with V-shaped bent portions formed on resilient spring contacts such as 41v (see Fig. 6). In the particular embodiment illustrated, there are four such contacts 41, 42, 43 and 44 extending across the base from one side toward the other. The contacts 41 and 43 are provided with an enlargement, 41' and 43 respectively, resting upon elevated ledges of the base formed above the floor, while the contacts 42 and 44 are joined at one end by a connecting portion 45 also resting upon a ledge above the floor of the base but upon the opposite side of the spindle from the contacts 41 and 43. The contacts are each spaced at a different distance from the switch axis so that the four different cam tracks on the bottom surface of the cover may engage and selectively control the movement of the contact strips individually. The contact strips are formed of thin sheet metal of good electrical conductivity such as Phosphor bronze or equivalent. The ends opposite the mounting portions 41', 43' and 45 of the contacts are free to move so as to engage and disengage fixed contact buttons formed upon a contact plate 46 or 47 as the case may be. Such contact plates 46 and 47 may be stamped from sheet metal and secured upon a ledge or ledges of the base above the floor.

The fixed contact plates 46 and 47 as well as the anchored ends of the movable contact members 41, 43 and 45 are efficiently and economically secured to the base by terminal pieces (for example, see 49 in Fig. 4). These terminal pieces may be stamped from sheet metal and bent into L-shape with the longer portion extending through slots or passages from the bottom of the base, and through registering apertures in the parts 41, 43 and 45-47. The ends of the terminal pieces which extend through those parts are peaned over, while the bent-over opposite ends lie against the bottom side of the base and may conveniently be tapped for a reception of binding screws. Thus the contacts are securely attached to the base in an economical fashion by parts which are inexpensively stamped and can be assembled with the maximum economy.

The cover may be conveniently held or indexed in several different rotary positions by a star-shaped boss ramm d Feb. 28, 1956 21 formed upon the cover and extending coaxially from the underside thereof. Pressing into the several indentations of the boss are a pair of balls 52 urged oppositely radially inward by compressed coil springs 50 seated in recesses provided therefor in the floor of the base.

From the foregoing it will be apparent that I have provided a novel and economical means to attach a rotary switch-operating cover to a switch base in a shallow rotary type switch while at the same time there are,

embodied in the switch, novel" and economical expcdients making for manufacuring economy in the formation and assembly of the parts which go to make up the combination.

Many modifications within the scope of the invention will occur to those skilled in the art; Therefore, I do not limit the invention to the precise form and detail as illustrated and described.

What is claimed is:

17 In an electric switch, an insulating base hollowed out to provide a cavity for current-carrying switch parts, a rotatable switch-operating insulating cover cooperating with said base and covering said cavity, a spindle in said base on which said cover is mounted, said cover having a recess and said spindle having bifurcations on one end adapted to be bent down into said recess to retain said cover on said base, a flexible strip covering said recess, said strip having end portions adapted to become engaged with said cover upon bending of the strip to secure the strip removably on the cover.

2. In an electric switch, an insulating base hollowed out to provide a cavity for current-carrying switch parts,

a rotatable switch-operating insulating cover cooperating with said base and covering said cavity, a spindle in said base on which said cover is mounted, said cover having a recess and said spindle having bifurcations on one end adapted to be bent down into said recess to retain said cover on said base, a flexible strip covering said recess, said strip having bent ends adapted to resiliently engage diametrically opposite passages in said cover when said strip is flexed.

3. In an electric switch, an insulating base hollowed out to provide a cavity for current-carrying switch parts, a rotatable switch-operating insulating cover cooperating with said base covering said cavity, a spindle rotatively mounted in said base on which said cover is mounted, means permitting mounting of said cover on said base when all other parts have been mounted therein comprising a bifurcated end on said spindle, a recess in said cover adjacent said bifurcated end, into which the bifurcations may be bent over, and a flexible strip covering said recess and adapted to be attached to and removed from said cover by flexure, said strip when attached to the cover conforming substantially to the contour of the cover.

References Cited in the file of this patent UNITED STATES PATENTS 819,082 Setter May 1, 1906 1,672,123 Hartranft June 5, 1928 1,918,282 Meuer July 18, 1933 1,939,663 Cole Dec. 19, 1933 2,041,414 Johnson May 19, 1936 

